Data reading-writing method and device for remote data storage and system thereof

The invention discloses a data writing method for realizing remote data storage, which comprises the following steps: receiving a data writing request and requested write-in data; according to parameters used for determining sector numbers in the data writing request, determining the sector numbers which respectively correspond to all sectors used for storing the requested write-in data; respectively executing by aiming at each determined sector number; according to corresponding relations aiming at the block device identification-marked sector numbers of block device maintenance and marker bits in the data writing request, setting the marker bits which correspond to the sector numbers, wherein sectors marked by the sector numbers which correspond to the unset marker bits are used for storing the raw data of a block device or do not store the data, and the sectors marked by the sector numbers which correspond to the set marker bits are used for storing updated data of the block device; according to block device identifications, the sector numbers and arrow marks used for pointing to the updated data of the block device, generating corresponding key values; and correspondingly storing all the generated key values and the requested write-in data to remote storage resource pools.